Method and apparatus for scanning channel

ABSTRACT

Method and apparatus for scanning channels of a broadcast receiver are provided. The channel scanning method includes determining whether to perform an entire channel scanning operation or a partial channel scanning operation in response to a channel scan command, if the entire channel scanning operation is determined to be performed, performing the entire channel scanning operation by scanning all channels and storing channel information regarding a channel in which a broadcast signal exists in a channel map, and if the partial channel scanning operation is determined to be performed, performing the partial channel scanning operation by scanning a channel which is not registered in a pre-created channel map, and storing channel information regarding the non-registered channel in which a broadcast signals exists in the non-registered channel map.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No.61/095,677, filed on Sep. 10, 2008 and Korean Patent Application No.10-2009-0002630, filed on Jan. 13, 2009, the disclosures of which areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Apparatuses and methods consistent with the present invention relate toa broadcast receiver which performs channel scanning and a channelscanning method thereof, and more particularly, a broadcast receiverwhich efficiently performs channel scanning and a channel scanningmethod thereof.

2. Description of the Related Art

Due to the development of electronic technology, diverse broadcastservices such as analog broadcast, cable broadcast, digital satellitebroadcast, and digital terrestrial broadcast are supported by diverseapparatuses.

In addition, the number of broadcast channels that can be watched byusers are greatly increasing in recent years. Therefore, in order for auser to easily select a channel, related-art broadcast receivers supporta channel scanning function.

The channel scanning function is a function in which the broadcastreceiver tunes to reception band frequencies in sequence andautomatically stores information regarding a frequency channel throughwhich broadcast signals are received.

The channel scanning function allows the user to tune the broadcastreceiver to a channel by manipulating a channel up/down key withoutdirectly inputting a channel number.

However, if there is a change in the channel information, the usershould scan all of the channels to find a changed channel and wait untilall of the channels are scanned.

Accordingly, there is a need for a method for performing the channelscanning function more efficiently.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention overcome the abovedisadvantages and other disadvantages not described above. Also, thepresent invention is not required to overcome the disadvantagesdescribed above, and an exemplary embodiment of the present inventionmay not overcome any of the problems described above.

Exemplary embodiments of the present invention provide a broadcastreceiver which efficiently performs a channel scanning function and achannel scanning method thereof.

According to an aspect of the present invention, a channel scanningmethod of a broadcast receiver, includes determining whether to performan entire channel scanning operation or a partial channel scanningoperation in response to a channel scan command, if the entire channelscanning operation is determined to be performed, performing the entirechannel scanning operation by scanning all received physical channelsand storing channel information regarding at least one physical channelin which a broadcast signal exists in a channel map, and if the partialchannel scanning operation is determined to be performed, performing thepartial channel scanning operation by scanning at least one physicalchannel which is not registered in a pre-created channel map andadditionally storing channel information regarding the non-registeredchannel in which a broadcast signal exists in the channel map.

The determining operation may question a user about whether to performthe entire channel scanning operation or the partial channel scanningoperation in response to the channel scan command.

The partial channel scanning operation may include determining whether aphysical channel to be currently scanned is registered in thepre-created channel map, if the physical channel to be currently scannedis not registered in the channel map, tuning to the physical channel,determining whether a broadcast signal exists in the tuned physicalchannel, and if the broadcast signal exists in the tuned physicalchannel, additionally storing information regarding the physical channelin the channel map.

If the physical channel to be currently scanned is registered in thechannel map, the partial channel scanning operation may skip tuning tothe physical channel and determine whether a next channel is registeredin the channel map.

If the broadcast signals does not exit in the tuned physical channel,the partial channel scanning operation may determine whether a nextphysical channel is registered in the channel map.

The partial channel scanning operation may detect whether asynchronization signal exists in a signal received through thenon-registered channel to determine whether the broadcast signal existsin the non-registered channel.

According to an aspect of the present invention, a channel scanningapparatus of a broadcast receiver, includes a tuner which receives anddemodulates a broadcast signal of a channel selected from a plurality ofbroadcast channels by a user, a synchronization detector which extractsa synchronization signal from a video signal of the broadcast signals, auser interface which receives a control command to control an operationof the broadcast receiver, a micro computer which determines whether toperform an entire channel scanning operation or a partial channelscanning operation when a channel scan command is received through theuser interface, and, according to the determination, performs the entirechannel scanning operation or the partial channel scanning operation,and a channel map storage unit which stores a channel map which iscreated by performing a channel scanning operation.

According to another aspect of the present invention, a channel scanningmethod of a broadcast receiver, including scanning all received physicalchannels in response to a channel scan command and storing new channelinformation regarding a physical channel in which a broadcast signalexists to a first storage unit, comparing the new channel informationwith existing channel information stored in a second storage unit, ifthe new channel information is different from the existing channelinformation, questioning a user about whether to update the existingchannel information with the new channel information, and if a commandto update is received from the user, changing the existing channelinformation to the new channel information.

According to still another aspect of the present invention, a broadcastreceiver includes a channel map storage unit which stores a channel map,a user interface which receives a channel scan command, a tuner whichtunes only to a channel among all tunable channels that is notregistered in the channel map in sequence if a partial channel scancommand is input through the user interface, and a micro computer whichdetermines whether the channel tuned by the tuner is an effectivechannel through which a broadcast signal is received, and updates thechannel map according to a result of the determination.

According to still another aspect of the present invention, a channelscanning method of a broadcast receiver, includes, if a partial channelscan command is input, tuning to a channel among all tunable channelsthat is not registered in a channel map in sequence, and determiningwhether the channel tuned in sequence is an effective channel andupdating the channel map according to a result of the determination.

Accordingly, the channel scanning is efficiently performed.

Additional and/or other aspects and advantages of the invention will beset forth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will be moreapparent by describing certain exemplary embodiments with reference tothe accompanying drawings, in which:

FIG. 1 is a block diagram of a broadcast receiver according to anexemplary embodiment;

FIG. 2 is a flowchart illustrating a channel scanning method of abroadcast receiver according to an exemplary embodiment; and

FIG. 3 is a flowchart illustrating a channel scanning method of abroadcast receiver according to another exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Certain exemplary embodiments will now be described in greater detailwith reference to the accompanying drawings.

In the following description, the same drawing reference numerals areused for the same elements even in different drawings. The mattersdefined in the description, such as detailed construction and elements,are provided to assist in a comprehensive understanding of theinvention. Thus, it is apparent that the exemplary embodiments can becarried out without those specifically defined matters. Also, well-knownfunctions or constructions are not described in detail since they wouldobscure the invention with unnecessary detail.

FIG. 1 is a block diagram of a broadcast receiver according to anexemplary embodiment.

A broadcast receiver according to an exemplary embodiment may be anapparatus that can receive broadcast signals such as terrestrialbroadcast, satellite broadcast, and cable broadcast. More specifically,the broadcast receiver may be a television (TV) or a set-top box or maybe realized as various terminals that can receive broadcast signals. Thebroadcast receiver scans effective channels, in which broadcast signalsexist, in response to a channel scan command from a user, and creates achannel map using information regarding the effective channels. Thechannel map is used for controlling channel-related operations. That is,if the user manipulates a channel up/down key, the broadcast receivertunes to an adjacent channel in the channel map according to thedirection of manipulation and the number of manipulations, therebyreceiving the broadcast signals.

The broadcast receiver according to an exemplary embodiment may performan initial channel scanning operation with respect to all physicalchannels to determine whether broadcast signals exist in the channels,in response to an initial channel scan command. The broadcast receivermay determine whether to perform an entire channel scanning operation ora partial channel scanning operation in response to another channel scancommand.

If it is determined that the entire channel scanning operation is to beperformed, the channel scanning operation is performed with respect toall physical channels to determine whether a broadcast signal exists ineach of the channels, in the same way as the initial channel scanningoperation is performed.

If it is determined that the partial channel scanning operation is to beperformed, the channel scanning operation is performed with respect toonly a channel or channels which have not been registered in apre-created channel map, that is, a newly added channel(s).

As described, the user of the broadcast receiver can adaptively performthe entire channel scanning operation or the partial channel scanningoperation. Therefore, a time required to scan the channels can bereduced. If, however, all of the channels need to be scanned because thebroadcast receiver is moved to a new location, e.g., a new house, all ofthe channels can be updated rather than scanning only some of channels.

As shown in FIG. 1, a broadcast receiver 100 according to an exemplaryembodiment includes a tuner 105, a demultiplexer 110, an audio decoder115, an audio signal processor 120, a speaker 125, a video decoder 130,a video signal processor 135, a display unit 140, a synchronizationdetector 145, a data storage unit 150, a channel map storage unit 155, auser interface 160, and a micro computer 170.

The tuner 105 receives and demodulates a broadcast signal of a channelwhich is selected from a plurality of broadcast channels received via asatellite reception antenna, a terrestrial reception antenna or a cableaccording to a tuning control signal of the micro computer 170.

The demultiplexer 110 separates an audio stream, a video stream, andsystem control data from the broadcast signal output from the tuner 105,and outputs them. If one or more additional data streams are included inthe broadcast signal, the additional data streams may be also separatedand output.

The system control data may be a program and system information protocol(PSIP). The PSIP is additional information for digital broadcastaccording to the Advanced Television System Committee (ATSC) standards,and provides a service such as classification of information transmittedvia a corresponding transmission channel and a program guide. The PSIPmay be used for creating the channel map.

The audio decoder 115 decodes the audio stream separated by and outputfrom the demultiplexer 110, restores it to an original audio signal, andthen outputs the original audio signal to the audio signal processor120.

The audio signal processor 120 converts the audio signal decoded by theaudio decoder 115 into a signal which can be output as audio through thespeaker 125, which is an audio output apparatus, and outputs the signal.

The video decoder 130 decodes the video stream separated by and outputfrom the demultiplexer 110, restores it to an original video signal, andthen outputs the original video signal to the video signal processor135.

The video signal processor 135 converts the video signal decoded by thevideo decoder 130 into a signal which can be output as video through thedisplay unit 140, which is a video output apparatus, and outputs thesignal.

The synchronization detector 145 extracts a synchronization signal fromthe video signal output from the video decoder 130 and outputs theextracted signal to the micro computer 170. The synchronization signalmay be used for determining whether a broadcast signal exists in aphysical channel tuned by the tuner 105.

The data storage unit 150 stores the system control data separated bythe demultiplexer 110. The system control data stored in the datastorage unit 150 may be used for creating the channel map which is usedfor controlling a channel-related operation.

The channel map storage unit 155 stores the channel map which is createdthrough the channel scanning operation. The channel map containsinformation regarding effective channels in which broadcast signalsexist. The information regarding each effective channel is obtainedbased on the virtual channel table (VCT) of the PSIP which is the systemcontrol data, and includes broadcasting station information (a sourceidentification (ID)), a channel name, a physical channel number, and avirtual channel number.

The information regarding the effective channels which are registered inthe channel map is updated with information which is newly provided whenthe tuning operation of the tuner 105 is performed in response to ageneral channel selection command. Therefore, it is not necessary toreceive information regarding a change in the channels which have beenpreviously registered through the channel scanning operation.

The user interface 160 receives a control command to control anoperation of the broadcast receiver 100 from the user and outputs thecontrol command to the micro computer 170.

The user interface 160 may be a key input unit provided on a main bodyof the broadcast receiver 100 or an infrared signal reception unit whichreceives an infrared signal transmitted from a remote controller (notshown), which is an external input apparatus, and transmits the infraredsignal to the micro computer 170.

The micro computer 170 controls operations of the broadcast receiver 100according to the user control commands input through the user interface160.

If a channel scan command is received from the user, the micro computer170 may display on the display unit 140 a message questioning aboutwhether the user wishes to perform the entire channel scanning operationor the partial channel scanning operation.

If the user wishes to perform the entire channel scanning operation, themicro computer 170 controls the tuner to scan all receivable physicalchannels, obtains channel information regarding physical channels inwhich broadcast signals exist, and stores the channel information on thechannel map storage unit 155. The existing channel information stored inthe channel map storage unit 155 is updated with the new channelinformation.

On the other hand, if the user wishes to perform the partial channelscanning operation, the micro computer 170 controls the tuner 105 totune to only channels among all receivable physical channels that arenot registered in the channel map of the channel map storage unit 155.

The channel scanning method may be selected in a different way.

If a “menu check command” is input through the user interface 160 (forexample, if the user presses a “Menu” button on the main body of thebroadcast receiver 100 or on the remote controller), an on screendisplay (OSD) including a “entire channel auto scanning” menu and a“partial channel auto scanning” menu may be displayed on the displayunit 140.

If the user selects the “entire channel auto scanning” menu, the microcomputer 170 controls the tuner 105 to tune to the entire tunablechannels in sequence. Among the broadcast channels tuned in sequence, abroadcast channel, from which a synchronization signal is detected, thatis, an effective channel, is identified, and a channel map is createdand stored in the channel map storage unit 155.

If the user selects the “partial channel auto scanning” menu, the microcomputer 170 checks the channel map pre-stored in the channel mapstorage unit 155. Accordingly, the auto scanning operation is performedwith respect to only the frequency channels other than the alreadyscanned channels so that the existing channel map is updated. In thiscase, if there is no information stored in the channel map regarding thepreviously scanned channel, the auto channel scanning operation for theentire channels may be performed even if the partial channel autoscanning is selected.

If the micro computer 170 receives a signal indicating that asynchronization signal exists in a video signal received via a channelcurrently tuned by the tuner 105 from the synchronization detector 145,the micro computer 170 determines that a broadcast signal exists in thecorresponding channel. In this case, the micro computer 170 obtainschannel information using the system control data included in thebroadcast signals received via the corresponding channel, and adds theobtained channel information to the channel map stored in the channelmap storage unit 155.

The respective components of FIG. 1 are illustrated only for the purposeof explaining the operations of the broadcast receiver 100, and somecomponents may be omitted and/or relationships among the components maybe changed. Also, components not illustrated in FIG. 1 may be added.

For example, the broadcast receiver 100 may include a channel mapstorage unit 155 to store a channel map, a user interface 160 to receivea channel scan command, a tuner 105 to tune to a channel among alltunable channels that is not registered in the channel map in sequenceif a partial channel scan command is input through the user interface160, and a micro computer 170 to determine whether the channel tuned bythe tuner 105 is an effective channel containing broadcast signals andupdate the channel map according to the result of determination.

FIG. 2 is a flowchart illustrating a channel scanning method of thebroadcast receiver according to an exemplary embodiment of the presentinvention.

Referring to FIG. 2, if a channel scan command is received through theuser interface 160 (S200), the micro computer 170 determines whether toperform an entire channel scanning operation or a partial channelscanning operation (S210). At this time, the micro computer 170 maydisplay on a screen a message questioning about whether the user wishesto perform an entire channel scanning operation or a partial channelscanning operation, so that the user can select one of the two channelscanning operations. Alternatively, a menu for an entire channelscanning and a menu for a partial channel scanning may be separatelyprovided on the menu of the broadcast receiver 100 so that the user candirectly select one of them. Also, an entire channel scan command keyand a partial channel scanning menu key may be separately provided onthe remote controller or on the main body of the broadcast receiver 100so that the user can select one of them.

If it is determined that the entire channel scanning operation isselected, the micro computer 170 scans all physical channels which arereceivable by the broadcast receiver 100, obtains channel informationregarding physical channels in which broadcast signals exist, and storesthe channel information in the channel map storage unit 155 (S220). Atthis time, existing channel information which is stored in the channelmap storage unit 155 is updated with the new channel information. Here,the above operation S220 may be performed according to operations S310,S320, S330, S340 and S350 as illustrated in FIG. 3 as explained later.

On the other hand, if it is determined that the partial channel scanningoperation is selected in operation S210, the micro computer 170determines whether a first scan target physical channel is a channelwhich is registered in the channel map of the channel map storage unit155 (S230).

This is because the partial scanning operation is performed with respectto only channels which are not registered in the channel map of thechannel map storage unit 155, that is, newly added channels, rather thanall receivable physical channels.

In general, in response to the channel scan command, the broadcastreceiver 100 scans all receivable physical channels in sequence from thelowest order channel to the highest order channel or from the highestorder channel to the lowest order channel. Therefore, a first scantarget physical channel may be the lowest order physical channel or thehighest order physical channel.

If it is determined that the first scan target physical channel isregistered in the channel map (S230-Y), the micro computer 170 skipstuning to the physical channel, and determines whether the next physicalchannel is registered in the channel map to determine whether to performthe channel scanning operation for the next channel (S240).

If it is determined that the first scan target physical search is notregistered in the channel map (S230-N), the micro computer 170 transmitsa tuning control signal to the tuner 105 to tune to the first scantarget physical channel (S250).

Next, the micro computer 170 determines whether a broadcast signalexists in the physical channel tuned by the tuner 105 (S260). Morespecifically, the micro computer 170 determines whether a broadcastsignals exists in the physical channel tuned by the tuner 105 bydetermining whether a synchronization signal exists in a video signalreceived through the channel tuned by the tuner 105.

If it is determined that a broadcast signal does not exist in thephysical channel tuned by the tuner 105 (S260-N), the micro computer 170returns to operation S240 to determine whether to perform a scanningoperation for the next physical channel.

If it is determined that a broadcast signal exists in the physicalchannel tuned by the tuner 105 (S260-Y), the micro computer 170 obtainschannel information using system control data included in the broadcastsignal received via the physical channel, and additionally stores theobtained channel information in the channel map stored in the channelmap storage unit 155 (S270, S280).

Then, the micro computer 170 determines whether the currently scannedphysical channel is a final physical channel to be scanned (S290).

If it is determined that the currently scanned physical channel is afinal physical channel to be scanned (S290-Y), the channel scanningoperation is finished. If it is determined that the scanned physicalchannel is not a final physical channel to be scanned (S290-N), themicro computer 170 returns to operation S240 to determine whether toperform scanning operation for the next physical channel.

In the above exemplary embodiment, although a skipping or tuningoperation is determined by determining whether each channel isregistered in the channel map, this should not be considered aslimiting. That is, if a partial channel scan mode is determined,information regarding an existing channel map is read out so thatinformation regarding channels among the entire channel band that arenot scanned can be collectively identified. After that, the identifiedchannels are tuned in sequence and it is determined whether the channelsare effective channels, and then according to a result of determination,the channel map is updated.

According to another exemplary embodiment, the partial channel scanningis not performed with respect to the entire channels which are notregistered in the channel map, and is performed with respect to only achannel which has been once registered in a previous channel map but isdeleted from the channel map in the updating process, or only a channelwhich is never scanned and thus cannot identify whether it containsbroadcast signals.

Also, if the broadcast receiver 100 can tune to various types ofbroadcast signals such as satellite antenna signals, terrestrialsignals, and cable signals as described above, it can perform a partialchannel scanning operation according to the type of broadcast signals.For example, if the entire channel scanning is selected, the broadcastreceiver 100 tunes to all supportable types of broadcast signal channelsin sequence, and if the partial channel scanning is selected, thebroadcast receiver 100 selectively performs non-searched channelscanning, satellite antenna signal channel scanning, terrestrial signalchannel scanning, or cable signal channel scanning.

FIG. 3 is a flowchart illustrating a channel scanning method of thebroadcast receiver according to another exemplary embodiment.

Referring to FIG. 3, if a channel scan command is received through theuser interface 160 (S300), the micro computer 170 scans all physicalchannels that can be accessed by the broadcast receiver 100, obtainschannel information regarding physical channels in which broadcastsignals exist, and stores the channel information in an extra storageunit (not shown) (S310).

After the micro computer 170 finishes scanning all physical channels inoperation S310, the micro computer 170 compares existing channelinformation which is stored in the channel map storage unit 155 with thenew channel information which is stored in the extra storage unit(S320).

If the new channel information stored in the extra storage unit is thesame as the existing channel information stored in the channel mapstorage unit 155, the channel scanning is finished.

However, if the new channel information stored in the extra storage unitis different from the existing channel information stored in the channelmap storage unit 155, the micro computer 170 displays on the displayunit 140 a message questioning whether the user wishes to update theexisting channel information stored in the channel map storage unit 155with the new channel information stored in the extra storage unit(S330).

The micro computer 170 may add only the new channel informationregarding a channel that does not exist in the channel informationstored in the channel map storage unit 155, rather than updating theexisting channel information stored in the channel map storage unit 155with the new channel information stored in the extra storage unit. Atthis time, the micro computer 170 may display a screen questioning aboutwhether the user wishes to update or add the channel information (S330).

If the user wishes to update the channel information (S330-Update), themicro computer 170 changes the existing channel information stored inthe channel map storage unit 155 to the new channel information storedin the extra storage unit (S340).

If the user wishes to add the channel information in operation S330, themicro computer 170 additionally stores only the new channel informationregarding the channel that does not exist in the existing channelinformation stored in the channel map storage unit 155, in the channelmap storage unit 155 (S350).

Accordingly, the user can add the new channel information without anyloss of the existing channel information.

According to the exemplary embodiments, one or more of the followingadvantages may be achieved.

Since the user can determine whether to perform an entire channelscanning operation or a partial channel scanning operation, the user mayadaptively perform the entire channel scanning operation or the partialchannel scanning operation according to the situations.

Also, the partial channel scanning operation may reduce the channelscanning time compared to the entire channel scanning operation.

Also, even if the entire channel scanning operation is performed, newchannel information may be additionally stored without any loss of theexisting channel information.

The present invention is not limited to the above-mentioned advantagesand other advantages not mentioned above can be understood by thoseskilled in the art from the description of the appended claims.

The foregoing exemplary embodiments and advantages are merely exemplaryand are not to be construed as limiting the present invention. Thepresent teaching can be readily applied to other types of apparatuses.Also, the description of the exemplary embodiments of the presentinvention is intended to be illustrative, and not to limit the scope ofthe claims, and many alternatives, modifications, and variations will beapparent to those skilled in the art.

1. A channel scanning method of a broadcast receiver, the methodcomprising: if a channel scan command is not an initial channelscanning, determining whether to perform an entire channel scanningoperation or a partial channel scanning operation in response to thechannel scan command; if it is determined that the entire channelscanning operation is to be performed, performing the entire channelscanning operation by scanning all channels and storing channelinformation regarding at least one channel in which a broadcast signalexists in a channel map; and if it is determined that the partialchannel scanning operation is to be performed, performing the partialchannel scanning operation by scanning at least one channel which is notregistered in the channel map, and storing channel information regardingthe non-registered channel in which the broadcast signal exists in thechannel map.
 2. The channel scanning method as claimed in claim 1,wherein the determining comprises outputting a message questioningwhether to perform the entire channel scanning operation or the partialchannel scanning operation in response to the channel scan command. 3.The channel scanning method as claimed in claim 1, wherein the partialchannel scanning operation comprises: determining whether a channel tobe currently scanned is registered in the channel map; if it isdetermined that the channel to be currently scanned is not registered inthe channel map, tuning to the channel to be currently scanned;determining whether a broadcast signal exists in the tuned channel; andif it is determined that the broadcast signal exists in the tunedchannel, storing information regarding the tuned channel in the channelmap.
 4. The channel scanning method as claimed in claim 3, wherein thepartial channel scanning further comprises, if it is determined that thechannel to be currently scanned is registered in the channel map,skipping tuning to the channel to be currently scanned, and determiningwhether a next channel is registered in the channel map.
 5. The channelscanning method as claimed in claim 3, wherein the partial channelscanning further comprises, if it is determined that the broadcastsignal does not exit in the tuned channel, determining whether a nextchannel is registered in the channel map.
 6. The channel scanning methodas claimed in claim 1, wherein the partial channel scanning operationcomprises detecting whether a synchronization signal exists in thenon-registered channel to determine whether the broadcast signal existsin the non-registered channel.
 7. A channel scanning apparatus of abroadcast receiver, comprising: a tuner which receives and demodulates abroadcast signal of a channel selected from a plurality of broadcastchannels; a user interface through which a channel scan command isinput; a micro computer which, if the channel scan command is not aninitial channel scanning, determines whether to perform an entirechannel scanning operation or a partial channel scanning operation inresponse to the channel scan command input through the user interface,and performs the entire channel scanning operation or the partialchannel scanning operation according to a result of the determination.8. The channel scanning apparatus as claimed in claim 7, wherein themicro computer displays on a display unit a message questioning whetherto perform the entire channel scanning operation or the partial channelscanning operation in response to the channel scan command.
 9. Thechannel scanning apparatus as claimed in claim 7, further comprising achannel map storage unit that stores a channel map storing channelinformation, wherein if the channel scan command requests the partialchannel scanning operation, the micro computer determines whether achannel to be currently scanned is registered in the channel map,wherein if it is determined that the channel to be currently scanned isnot registered in the channel map, the micro computer tunes to thechannel to be currently scanned, and determines whether a broadcastsignal exists in the tuned channel, and wherein if it is determined thatthe broadcast signal exists in the tuned channel, the micro computerstores channel information regarding the tuned channel in the channelmap.
 10. The channel scanning apparatus as claimed in claim 9, whereinif it is determined that the channel to be currently scanned isregistered in the channel map, the micro computer skips tuning to thechannel to be currently scanned, and determines whether a next channelis registered in the channel map.
 11. The channel scanning apparatus asclaimed in claim 9, wherein if it is determined that the broadcastsignal does not exit in the tuned channel, the micro computer determineswhether a next channel is registered in the channel map.
 12. The channelscanning apparatus as claimed in claim 7, further comprising asynchronization detector that extracts a synchronization signal from avideo signal of the broadcast signal, wherein, if a signal, indicatingthat the synchronization signal exists in the video signal receivedthrough a channel currently tuned by the tuner, is received from thesynchronization detector, the micro computer determines that thebroadcast signal exists in the channel.
 13. A channel scanning method ofa broadcast receiver, the method comprising: scanning all channelsreceived by the broadcast receiver in response to a channel scan commandand storing new channel information regarding a channel in which abroadcast signal exists to a first storage unit; comparing the newchannel information with existing channel information stored in a secondstorage unit; if the new channel information is different from theexisting channel information, outputting a message questioning whetherto update the existing channel information stored with the new channelinformation or not; and if a command to update is received in responseto the message, changing the existing channel information to the newchannel information.
 14. The channel scanning method as claimed in claim13, further comprising, if the new channel information is different fromthe existing channel information, outputting another message questioningwhether to add information among the new channel information that is notstored in the second storage unit to the second storage unit.
 15. Thechannel scanning method as claimed in claim 14, further comprising, if acommand to add is received in response to the other message, adding theinformation among the new channel information that is not stored in thesecond storage unit.
 16. A broadcast receiver comprising: a channel mapstorage unit which stores a channel map; a user interface which receivesa channel scan command; a tuner which tunes only to a channel, among alltunable channels, that is not registered in the channel map if a channelscan command is input through the user interface; and a micro computerwhich determines whether the channel tuned by the tuner is an effectivechannel through which a broadcast signal is received, outputs a messagequestioning whether to add the channel which is determined to be aneffective channel and, if a command to add the effective channel isreceived in response to the message, adds the effective channel on thechannel map.
 17. A channel scanning method of a broadcast receiver, themethod comprising: if a channel scan command is input, tuning to achannel, among all tunable channels, that is not registered in a channelmap; and determining whether the tuned channel is an effective channelthrough which a broadcast signal is received; outputting a massagequestioning whether to add the channel which is determined to be aneffective channel; and if a command to add the effective channel isreceived in response to the message, adding the effective channel on thechannel map.
 18. A broadcast receiver comprising: a tuner which tunes toa channel selected among channels that are accessible by the broadcastreceiver; a channel scanning unit which performs a channel scanningoperation scanning the channels to determine if broadcast signals existin the channels; a channel map storage unit which stores channelinformation on the channels including the tuned channel obtained by thechannel scanning operation; and a micro computer which controls thechannel scanning unit to scan the channels, outputs a messagequestioning whether to update a channel in which it is determined thatbroadcast signals exist, and if a command to update the channel isreceived in response to the message, updates the channel information.